Definition of velamen in English:
velamen
nounPlural velamina vɪˈleɪmənvəˈlāmən
Botany An outer layer of empty cells in the aerial roots of epiphytic orchids and aroids.
Example sentencesExamples
- Orchid roots are covered with a special tissue called velamen occurring only in a very few non-orchid plant families.
- The role of the velamen is to absorb moisture from the ambient atmosphere, and, may be, to protect from cold or heat.
- Over watering turns the velamen brown and mushy and the roots lose their ability to absorb water.
- When water is in short supply, the dry velamen restricts water loss from the roots.
- While dry, the velamen may provide a barrier to water loss via transpiration from the wet, internal cells of the root.
Origin
Late 19th century: from Latin, from velare 'to cover'.